By virtue of today's apex court verdict, Tamil Nadu, Karnataka, Kerala and Union Territory Puducherry would be annually entitled to 404.25 tmcft, 284.75 tmcft, 30 tmcft and 7 tmcft of Cauvery water respectively out of a total of 740 tmcft.

The Supreme Court today raised the 270 tmcft share of Cauvery water for Karnataka by 14.75 tmcft and reduced Tamil Nadu's share while compensating it by allowing extraction of 10 tmcft groundwater from the river basin, saying the issue of drinking water has to be placed on a "higher pedestal".

By virtue of today's apex court verdict, Tamil Nadu, Karnataka, Kerala and Union Territory Puducherry would be annually entitled to 404.25 tmcft, 284.75 tmcft, 30 tmcft and 7 tmcft of Cauvery water respectively out of a total of 740 tmcft.

Besides this, 10 thousand million cubic feet (tmcft) of water would be used for environment protection and 4 tmcft would be kept for inevitable escapages into the sea.

The Cauvery Water Dispute Tribunal (CWDT) award of February 5, 2007, which was notified in the gazette on February 19, 2013, had allocated 419 tmcft , 270 tmcft, 30 tmcft and 7 tmcft of water yearly to Tamil Nadu, Karnataka, Kerala and Puducherry respectively.

The top court concurred with the 2007 findings of the CWDT with regard to the water share of 30 tmcft to Kerala and 7 tmcft to Puducherry.

A three-judge bench headed by Chief Justice Dipak Misra justified the increase in Karnataka's share by taking note of the principle on drinking water and the "global status" acquired by the state capital and the IT city of Bengaluru.

"Drinking water requirement of the overall population of all the states has to be placed on a higher pedestal as we treat it as a hierarchically fundamental principle of equitable distribution," the bench said.

"The tribunal had drastically reduced the share of Karnataka towards domestic and industrial purpose for the reason being that only 1/3rd of the city of Bengaluru falls within the river basin and also on the presumption that 50 per cent of the drinking water requirement would be met from ground water supply. The said view taken by the tribunal ignores the basic principle pertaining to drinking water and is, thus unsustainable. Keeping in mind the global status that the city has attained, an addition of 4.75 tmc is awarded to Karnataka," the bench, also comprising Justices Amitava Roy and A M Khanwilkar, said.

Out of the enhanced 14.75 tmcft of water in Karnataka's share, 10 tmcft has been increased on account of availability of ground water in Tamil Nadu.

The bench granted six weeks time to the Centre to formulate a scheme to ensure compliance of its 465-page judgement, which modified the CWDT award and made it clear that it will not be extending time for this on any ground.

It said the order on Cauvery water allocation will continue for the next 15 years.

The top court did not agree with the findings of the tribunal that the data on availability of ground water in Cauvery basin in Tamil Nadu was based on conjecture and allowed the state to extract 10 tmcft, out of 20 tmcft groundwater.

"The admission of facts along with the confirmatory empirical data suggests that around 20 tmc of groundwater is available beneath the surface in Tamil Nadu which the Tribunal has not taken into account citing it as a conjecture. We, while keeping in mind the risks associated with over-extraction of underground water, deem it fit that 10 tmc of the said available groundwater in Tamil Nadu can, in the facts and circumstances of the present case, be accounted for in the final determination of its share," it said.

Now, Karnataka will have to release 177.25 tmcft of water at the inter-state border with Tamil Nadu at Billigundulu.

The court, which referred to international rules of Helsinki, Compione and Berlin on equitable distribution of river waters passing through various nations, said that river is a national asset and no state can claim "exclusive ownership" of such waters or deprive other states.

"The waters of an inter-state river passing through the corridors of the riparian states constitute national asset and cannot be said to be located in any one state. Being in a state of flow, no state can claim exclusive ownership of such waters or assert a prescriptive right so as to deprive the other States of their equitable share," it said.

The bench said "It has been propounded therein that the right to flowing water is well-settled to be a right incident to property in the land and is a right publici juris of such character, that while it is common and equal to all through whose land it runs and no one can obstruct or divert it, yet as one of the beneficial gifts of nature, each beneficiary has a right to just and reasonable use of it."

It rejected the Centre's contention that the court should not issue any direction by keeping in mind the bar imposed under Article 363 of the Constitution which deals with the restrictions put on courts in interfering in disputes arising out of "certain treaties, agreements, etc".

"The issues in this case have no connection, whatsoever, with the concepts of sovereignty and integrity of India and, therefore, the bar under Article 363 of the Constitution is not attracted," the bench said.

The court, which decided the appeals and cross-appeals of Karnataka, Tamil Nadu and Kerala against the 2007 arbitral award, considered the materials brought on record by the parties and said the final determination of the irrigated area arrived at by the tribunal for Tamil Nadu, cannot be declared incorrect or fallacious.

"We do not find any perversity of approach in the tribunal's findings with regard to the allocation of water for domestic and industrial purposes in the State of Tamil Nadu. Hence, the same requires no interference," it said.

The bench said that in view of the "acute scarcity of the water resources" and the intensely contested claims of the states, it is expected that the allocations hereby made would be utilised for the purposes earmarked and accepted and "no deviancy is shown in carrying out the verdict of this court".

On September 30, 2016, it had pulled up Karnataka for its repeated "defiance" in flouting its orders on the issue and said no one would know when the "wrath of the law" would fall on it.

Later, Karnataka had moved a review petition in the apex court against its three orders on the matter and direction to the Centre to create the Cauvery Water Management Board (CWMB). It said "grave miscarriage of justice" was caused to it following the three apex court orders of September 20, 27 and 30, 2016, by which it was directed to release water.

Tamil Nadu had earlier alleged that Kerala was drawing water in excess of what was allocated to it by the tribunal.

The apex court had on December 9, 2016 upheld the maintainability of appeals filed by the riparian states, saying it has the "jurisdiction to decide the parameters, scope, authority and jurisdiction of the tribunal".

The court had rejected the Centre's objection that the CWDT award amounted to a final decree and it had no jurisdiction to hear the appeals against the award.